The Science Of Sleep (Michel Gondry) Gael Garcia Bernal, Charlotte Gainsbourg, Alain Chabat, Pierre Vaneck. Running time: 105 minutes . . .

IF there is one thing Michael Gondry's 'The Science Of Sleep' is not, it is scientific. We figure this out pretty smart when Stephane (Gael Garcia Bernal) tells us on his imaginary TV show that the brain is the most complex thing in the universe - "And it is right behind the nose". In the strange world of The Science Of Sleep - a world filled with cardboard TV stations, fluffy clouds held aloft by piano chords and human flight over underwater cities - it is the only fact clear as the nose on your face. Everything else will have you reaching for the back of your head.

But the other half of the film's title lives up to billing: it is very, very sleepy. It's made up of the essence of dreams - the silly poetry that occurs when you just wake up and your head is still clouded with dream-fog. If watching a David Lynch film can invoke the dissolving, inexplicable world of the REM dream, then The Science Of Sleep is the surreal, cinematic equivalent of the waking dream.

French director Michel Gondry, whose previous film was the wonderfully mind-bending Eternal Sunshine Of The Spotless Mind, has written a film about dreaming that slowly takes the form of a dream itself. But watching it is like trying to decide if you are awake or asleep - it's so wilfully deceiving that you yearn for alarm-clock clarity to stir you out of the stupor.

It's certainly one of the most eccentric films this year.

It is a romantic fantasy set in Paris starring Gael Garcia Bernal.

He is an illustrator from Mexico who has a major difficulty discerning reality from his dreams. Languages slide from French to English to Spanish, and most of the action takes place inside his head. And what a strange world that is. It's like a wonderful melange of kooky children's TV and cheap stop-motion animation, all designed to give an ironic childishness to his inner thoughts.

Within this nebulous haze lies a story of unrequited love. We first meet Stephane (played by Garcia Bernal with a mixture of comic edge and wounded boy sensibility) as he arrives in Paris. His father has died, and at his mother's bidding, he comes to live in the apartment in which he grew up. He tries on his father's old suit and uses his old electric shaver. His childhood bedroom has been preserved - full of toys and fantastic objects. At night he beds down in silly pyjamas and dreams of Stephane TV - a nightly show where he talks to cardboard cameras about the science of sleep while images of his younger self, fooling around with his father, play on a TV screen behind him.

By day, he works at a job arranged for him by his mother at a calendar company. But it has little room for his unique talents - strange, childish drawings of airplane crashes, earthquakes and other catastrophes that he calls 'disasterology', so he spends his day cutting and pasting calendars and dealing with Guy (Alain Chabat), a rowdy colleague who talks about his conquests with women.

But Stephane's sleep is troubled too by the opposite sex (although he does have his fair share of anxiety dreams, including an amusing scene in which he lumbers slowly in work with giant hands). He is in love with Stephanie (Charlotte Gainsbourg), his neighbour from the flat across the hall. She shares his love of childish things; he woos her with his inventions (the director has great fun in the film with a one-second time machine). But Stephane can't connect with reality and his increasingly erratic behaviour pushes Stephanie away.

He slides even deeper into his imaginary world, like a pained little boy.

The plot is concerned more with what Stephane is thinking and feeling than with what he is doing, and gradually the film does away with the conventions that allow us to tell what is real from not. Reality soon becomes just as wacky as the dream world and you quickly lose your bearings. Gondry is by no means the first director to blur boundaries in such a fashion (just think of directors Luis Bunuel and David Lynch). And indeed, there is no requirement that states we have to have a complete handle on a film in order to appreciate the power it has over us. But underneath this eccentric canvas lies a more conventional story of unrequited love that presses a need on us to be understood. The film might be better read as a study of grief: hovering in the wings of Stephane's mind is his father, and as Stephane unplugs from reality, burrowing deeper into lost childhood, he acts like a person dislocated by loss. He is sleepwalking through his sorrow. The Science Of Sleep just might be one of the strangest films about grief ever made.

Watching this feels like peering into a dazzling, child-like imagination. But I wonder how the story would have shaped up had Gondry worked on this with scriptwriter Charlie Kaufman, as he did before on Eternal Sunshine Of The Spotless Mind. Kaufman has a gift for harnessing the weird and wonderful with clarity and structure; Gondry, just like his character Stephane, seems unable to connect all his wonderful images and feelings into something that has emotional impact. His wonderfully realised dream dissipates under the hard light of day.